I’m pretty sure that most of you reading this are guilty of knocking up a quick sarnie without washing your hands before, but you might just think again when you see the photo below that was recently shared on Facebook.

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Teacher Donna Allen from North Carolina conducted her “grossest yet coolest experiment” while teaching her pupils about germs and how they spread. She got her kids to put a piece of bread in a baggy with a glove on (controlled), then one where the kids had washed their hands (clean) and then one where every kid touched the bread without washing their hands (dirty).

She decided to share the results on Facebook and let’s just say, it ain’t pretty:

Gross. Just look at how mouldy the dirty baggy bread has gone. That’s the last time I ever make a sandwich, or any food for that matter, without washing my hands first. You might not be able to seem the germs but there’s no denying that they’re there.

While we’re on the topic of sandwiches, check out these 20 sarnies that will sort out your hangover. You should definitely make one of these for breakfast tomorrow morning – just make sure you wash your hands first.